otto, diesel, and rotary engine cycles arenas alejandro julian thompson daniel vertucci matthew...
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Otto, Diesel, and Rotary Engine Cycles
Arenas Alejandro
Julian Thompson
Daniel Vertucci
Matthew White
Otto Engine
Few things to remember• Invented by Nikolas Augustus Otto in the 1870’s.• Also know as the four-stroke engine because of its four-
stroke cycle.• Internal combustion engine.• Most commonly used for automotive industrial purposes.• Used for cars, truck, generators, planes, and more.• Requires a sparkplug in order to begin combustion
Four-stroke Cycle
•Intake Stroke•Compression Stroke•Power Stroke•Exhaust Stroke
Intake Stroke
Compression Stroke
Power Stroke
Exhaust Stroke
Four-stroke cycle
1. Intake Cycle2. Compression
Cycle3. Power Cycle4. Exhaust Cycle
Otto Cycle Diagram
There are a few differences between the diesel engine and the gasoline engine.
•A gasoline engine intakes a mixture of gas and air, compresses it and ignites the mixture with a spark. A diesel engine takes in just air, compresses it and then injects fuel into the compressed air. So the diesel engine does not need a spark plug to operate. The heat of the compressed air lights the fuel spontaneously.
•A gasoline engine compresses at a ratio of 8:1 to 12:1, while a diesel engine compresses at a ratio of 14:1 to as high as 25:1. The higher the compression ratio of the diesel engine leads to better efficiency and more power.
•Gasoline engines generally use either carburetion, in which the air and fuel is mixed long before the air enters the cylinder, or port fuel injection, in which the fuel is injected just prior to the intake stroke (outside the cylinder). Diesel engines use direct fuel injection -- the diesel fuel is injected directly into the cylinder.
Diesel fuel is heavier and oilier than regular gasoline and it smells different. Diesel gas evaporates much more slowly than gasoline because it is heavier. Its chemical compound is C14H30 as compared to gasoline which is C9H20. It takes less refining to create diesel fuelwhich is why it is usually cheaper than gasoline. It has a higher energy density than gasoline.One gallon of diesel fuel contains 155 million joules of energy compared to 132 million with gasoline. The fact that diesel fuel has a higher energy density and diesel engines run more efficiently than gasoline engines creates better mileage when traveling.
The main difference between a gasoline engine and a diesel engine is the spark plug.The injector has to be able to withstand the temperature and pressure inside the cylinder and still deliver fuel in a fine mist. The injection process is also different from gasoline engines. In gasoline engines fuel is injected into the cylinder during Intake stroke and then compressed. The fuel and air mixture limits the compression Ratio of the engine. If the air is compressed to much then the fuel spontaneously Ignites and creates knocking. A diesel compresses air only, so the compressionRatio can be much higher. The diesel cycle includes 4 stages which are the intake Of air, compression of air, fuel injection, and then the exhaust stage. The higher the compression ratio the more horsepower from the engine. It is the heat of the compressed air that ignites the fuel.
Rotary Engines
Rotation and Orbit
• Each tip of the rotor follows a trochoidal path around the housing
Note: The shaft rotates three times for eachRotation of the orbit
Four-Stroke Cycle (Revisited)
• Intake Stroke
• Compression Stroke
• Power Stroke
• Exhaust Stroke
• Same as Otto/Diesel Engine
Rotary Cycle
• No cylinders or pistons
• Separate chambers of air
Intake Stroke
Compression Stroke
Power Stroke
Exhaust Stroke
• 3 Cycles occur simultaneously (120 degrees out of phase)
• Drives rotor around shaft
Mazda
• 1967 Cosmo Sport
• 2004 RX-8
Alternative Fuels for Gas and Diesel Engines
Biodiesel
•It can be made from many different types of plant oils
•Soy beans are the most commonly used.
•This makes biodiesel nontoxic and renewable when compared to fossil fuels
Biodiesel vehicles are starting to increase in popularity, especially among large fleets of vehicles
Park rangers in Yellowstone National park use biodiesel to decrease pollution from their pickups
Almost any type of diesel engine can be converted to run on biodiesel, like this hummer
Biodiesel doesn't hurt an engines performance, but increases safety
Biodiesel can help an engine run better because it acts as solvent
Natural Gas Vehicles
Natural gas is a fossil fuel that is usually found above and below oil deposits
The idea of using natural gas was first developed in the 1930s, but until the invention of the leak-proof pipe transporting gas was difficult
1. NGVs burn natural gas that is compressed and stored in cylinders.
2. When the engine is started, natural gas flows into a fuel line.
3. The gas then enters a regulator where its pressure is reduced.
4. The natural gas feeds into the engine through a fuel injection system where it’s combined with air. The fuel/air mixture is adjusted to burn most efficiently and with the least possible emissions.
5. Natural gas burns in the engine just like gasoline.
6. NGVs can be refueled by attaching a hose at the fueling point.
Number of Natural
Gas VehiclesNumber of Fueling
Stations
Argentina 1,200,000 1,105
Brazil 600,000 600
Pakistan 410,000 423
Italy 400,800 463
India 159,159 166
United States 130,000 1,300
China 69,300 270
Egypt 47,289 78
Venezuela 44,146 147
Ukraine 42,000 130
Source: International Association for Natural Gas Vehicles. Statistics on IANGV website on December 17, 2003.
http://www.biodiesel.org/
http://www.ngvc.org/ngv/ngvc.nsf
http://www.shermanlab.com/science/physics/thermo/engines/OttoG.php
http://www.geocities.com/henry_yu_84/illustratn/006e.jpg
http://www.rotaryengineillustrated.com/re101/mechanics1.php